Hybrid electric vehicles having improved fuel economy over internal combustion engine powered vehicles and other vehicles are quickly becoming more popular as a cost of fuel increases. Typically, the improved fuel economy is due to known technologies such as regenerative braking, electric motor assist, and engine-off operation.
Although the technologies improve fuel economy, there are drawbacks. One such drawback is that accessories powered by a fuel-powered engine no longer operate when the fuel-powered engine is not in operation. One major accessory that does not operate is an air-conditioning compressor, which helps to cool air in a passenger compartment of the vehicle. Ultimately, without the use of the compressor, the temperature of the air in the passenger compartment increases to a point above a desired set-point, and the fuel-powered engine of the vehicle must restart.
Accordingly, vehicle manufacturers have used a full electric compressor on hybrid vehicles. The full electric compressor operates whether the fuel-powered engine is operating or not. A significant disadvantage of the full electric compressor is the inefficiency that occurs from converting engine shaft power to electricity, then electricity back to compressor shaft power. Thus, the use of a hybrid compressor which is mechanically and electrically driven is advantageous.
One such hybrid compressor is described in U.S. Pat. No. 6,543,243 entitled HYBRID COMPRESSOR, hereby incorporated herein by reference in its entirety. The compressor includes two compressor assemblies inside a single housing which operate independently of each other. One of the assemblies is mechanically driven by a pulley system in mechanical communication with a fuel-powered engine of the vehicle. The other of the assemblies is electrically driven and can be used when the fuel-powered engine is off, or when an excess of battery power is present. Therefore, it is possible to operate the compressor at maximum efficiency without impacting the temperature of the passenger compartment of the vehicle.
Although the aforementioned hybrid compressors operate efficiently, the compressors are difficult to package in an existing single compressor envelope, and involve high manufacturing costs. Additionally, because each assembly typically discharges a compressed fluid to a common discharge chamber, the operation of one assembly can interfere with the operation of the other assembly. Flow interference between the fluids discharged from the respective assemblies reduces the operating efficiency of the compressor and increases a noise generated thereby that is perceptible by passengers of the vehicle. The reduced operating efficiency necessitates the use of a larger compressor to achieve a desired output of compressed fluid therefrom.
Accordingly, it would be desirable to produce a discharge chamber for a compressor, wherein an interference of discharge pulsations, a cost, and a space requirement thereof are minimized and an efficiency thereof is maximized.